Chemicals inducing acute irritant contact dermatitis mobilize intracellular calcium in human keratinocytes.

Abstract Intracellular Ca 2+ increase is a common feature of multiple cellular pathways associated with receptor and channel activation, mediator secretion and gene regulation. We investigated the possibility of using this Ca 2+ signal as a biomarker for a reaction to chemical irritants of normal human keratinocytes (NHK) in submerged primary cell culture. We tested 14 referenced chemical compounds classified as strong (seven), weak (four) or non- (three) irritants in acute irritant contact dermatitis. We found that the strong irritant compounds tested at 20–40 mM induced an intracellular Ca 2+ increase measurable by spectrofluorimetry in an automated test. Weak and non-irritant compounds however did not increase intracellular Ca 2+ concentration. We further investigated the mechanisms by which the amine heptylamine, classified as a R34 corrosive compound, increases intracellular Ca 2+ . Heptylamine (20 mM) induced an ATP release that persisted in the absence of intra- and extra-cellular Ca 2+ . In addition, we found that this ATP activates NHK purinergic receptors that subsequently cause the increase in intracellular Ca 2+ from sarcoplasmic reticular stores. We conclude that measuring the intracellular Ca 2+ concentration in NHK is a suitable and easy way of determining any potential reaction to soluble chemical compounds.